Study of the effect of dopant concentration on the optical uniformity and photorefractive properties of LiNbO$_3$ : Er : Zn single crystals

The physicochemical characteristics, optical uniformity and photorefractive properties of a series of four LiNbO$_3$ : Er : Zn single crystals have been studied. Single crystals have been obtained by the Czochralski method. The erbium content in the crystals was $\sim$ 0.5 mol.% and the zinc content in the crystals was $\sim$ 4.02, 4.41, 4.65, 4.66 mol.%. The dopant distribution in the LiNbO$_3$ : Er : Zn melt-crystal system has been studied, and the optimal concentration ranges of erbium and zinc in the initial melt have been determined. The ranges provide crystals with high chemical, optical uniformity and resistance to optical damage for applications in optoelectronics and laser technology.